positionhigh has evolved the original MicroDexed port of the popular Yamaha DX7 plugin synth into a fully-blown, self-contained FM synth/sequencer/groovebox!

The project combines a Teensy 4.1 with a TI PCM5102A stereo DAC, and a capacitive touch ILI9341 SPI display, plus PSRAM for holding samples. What began as Holger’s project to bring the DX7 sound to Teensy is now a complete workstation, featuring a large, touch-based UI, eight-track, sixteen-step, seven-note polyphonic chain-based and twelve-track four-pattern live sequencers, an eight-voice polyphonic oscillator based on Mutable Instruments’ Braids, and a Euclidean arpeggiator with 1/8-1/64 steps.

External MIDI devices can be incorporated via USB or mini TRS jacks, including MIDI CC for controlling input/parameters. Samples can be loaded from SD card to PSRAM, the latter of which is also used to add up to 60 seconds of global delay effects. A tracker-styled editor and web-based remote control are in progress.

Code, documentation, STL files for a 3d-printed enclosure, and more can be found in the project’s Codeberg repo, and the PCB can be ordered directly from PCBWay.